Physician Assistant - Medical. Assesses, plans and provides patient care under the supervision of a physician. Examines patient, performs comprehensive physical examinations, and compiles patient medical data, including health history and results of physical examination. May require a master's degree and must be a graduate of an accredited physician assistant program.
How much land does it take to support a human being? Boundaries of China superimposed upon those of the USA. Let's do the math again, but this time for the entire planet. The total land surface area of Earth is about 57,308,738 square miles, of which about 33% is desert and about 24% is mountainous. Subtracting this uninhabitable 57% (32,665,981 mi2) from the total land area leaves 24,642,757 square miles or 15.77 billion acres of habitable land.
Radius of earth is about 6371 km. So total surface area is 5.1E8 km^2. There are 9.29E8 ft^2 in a km^2, so total area of earth's surface in square feet is 47.4E16 ft^2. About 29% of earth's surface is land, so land area is 13.74E16 ft^2. Steve Williams' answer gives 6.81E14 ft^2 habitable area. Which would imply only 0.49% of land surface is habitable.